To provide an on-vehicle heating unit using a ceramic PTC heater capable of heating a drink can by installing the ceramic PTC heater on a bottom part of a drink can holder installed in a cabin in a passenger car or the like.

The on-vehicle heater is constituted by a cylinder holder 1 with a bottom having a diameter and height capable of storing the drink can of a coffee or the like; and a heat generation body 3 having a connector 2 installed on the inner bottom part of the cylinder holder 1 with the bottom and connected to an insertion port for a cigar lighter of the vehicle. The heat generation body 3 comprises the ceramic PTC heater 5 capable of heating to a constant temperature; a negative electrode plate 6 and a positive electrode plate 7 for forming a projection-circular drink can placement surface made of aluminum metal for clamping and laminating the ceramic PTC heater 5 in a sandwich shape; and a heat resistant insulation resin 9 for separately insulating/retaining the positive and negative electrode plates 6, 7.